Share this post

Link to post

Share on other sites

all these bushcraft knives which are copies of the ray mears knife and no takers yet ??? you lot are allways asking for them , they are as cheap they ever will be im undercutting everyone else with these guys .

It is an idea that has been floating around in my head for a while....using wast oil to fire a forge up to welding temp. Anyone that does much forge welding knows fuel is expensive!

I was looking to keep it as simple as possible so gravity fed fuel and low pressure air with no fancy nozzles to get clogged.

This is the solution i came up with.

Based around an old propane bottle. Filled with water and cut top and bottom off.

P1090436 by Terry Griffiths, on Flickr">P1090437 by Terry Griffiths, on Flickr">P1090438 by Terry Griffiths, on Flickr">

Brake disk welded on vent end and an old chimney pot for the inner skin.
P1090440 by Terry Griffiths, on Flickr">P1090442 by Terry Griffiths, on Flickr">P1090443 by Terry Griffiths, on Flickr">

Ceramic wool on the inside of the door, base and between the pot and the steel bottle.
P1090444 by Terry Griffiths, on Flickr">P1090445 by Terry Griffiths, on Flickr">

Painted rigidizer on the ceramic wool on the door and around the pot, layed a piece op polythene on and closed tight and let it dry. The pot was left 20mm proud so it pushed into the wool and formed a checked seal.
P1090446 by Terry Griffiths, on Flickr">

Cored a hole through the lot for the burner.
P1090447 by Terry Griffiths, on Flickr">P1090448 by Terry Griffiths, on Flickr">

Burner 50mm scaffold pipe with stainless milker nipple nozzle on the end. Something like a 8mm steel pipe down the middle for an oil feed. Initially i left the end of the air pie restricted thinking it would spray the oil better but it restricted the air flow too much so i cut it back to nearly full bore.
P1090449 by Terry Griffiths, on Flickr">P1090450 by Terry Griffiths, on Flickr">P1090451 by Terry Griffiths, on Flickr">P1090453 by Terry Griffiths, on Flickr">P1090454 by Terry Griffiths, on Flickr">

After first fire the chimney pot is cracked but still in tact. I put o piece of stainless steel 6mm plate in the chamber where the oil lands. This needs to be red hot for the oil to vaporize and ignite. The first burn i just threw some paper and sticks in and lit them up then started injecting oil and air. For the next burn i added a quick hitch point pr a propane line to pre-heat before starting the oil injection.

P1090455 by Terry Griffiths, on Flickr">P1090456 by Terry Griffiths, on Flickr">

Pics of the assembled unit. Waste oil holder is just a plumbers gas bottle with the bottom cut off and a simple tap to control the oil flow.

P1090457 by Terry Griffiths, on Flickr">P1090458 by Terry Griffiths, on Flickr">P1090459 by Terry Griffiths, on Flickr">

Here she is on her maiden run at forging steel. Ever optimistic i went for forge welding straight off. About 12 strands of bed spring and 4 strips of file welded in a bundle then forge welded like a cable weld, twisting them together. These pics are all with the burner shut off, just the after glow!

P1090462 by Terry Griffiths, on Flickr">P1090463 by Terry Griffiths, on Flickr">P1090461 by Terry Griffiths, on Flickr">P1090465 by Terry Griffiths, on Flickr">P1090468 by Terry Griffiths, on Flickr">P1090469 by Terry Griffiths, on Flickr">

This thing pumps out insane heat. After running at welding temps for a couple of hours it has actually started to melt the fire-clay chimney pot! May replace it with fire-bricks or refractory, but will wait till it disintegrates,

P1090470 by Terry Griffiths, on Flickr">P1090471 by Terry Griffiths, on Flickr">

In summary: The whole thing was built entirely from scrap.The fuel is even free. The only thing i paid for was the ceramic wool and welding rods. Best used outside. It burns surprisingly clean but i wouldn't chance running it in an enclosed space. The blower is an old variable speed hoover...again off the dump. It pumps out insane heat but is quite adjustable. It will light up again without pre-heat half an hour after the previous shut down....just turn on the oil and air.

Finally here is the forge welded Damascus blank.

P1090474 by Terry Griffiths, on Flickr">P1090473 by Terry Griffiths, on Flickr">